[FFmpeg-devel] [PATCH v2] avfilter/vf_delogo: make the interp value compute method simple

[Limin Wang]

On Tue, Oct 08, 2019 at 10:47:56AM +0800, mypopy at gmail.com wrote:
> On Mon, Oct 7, 2019 at 11:14 PM Limin Wang <lance.lmwang at gmail.com> wrote:
> >
> > On Mon, Oct 07, 2019 at 01:12:46PM +0800, Steven Liu wrote:
> > > because the interp >= 0UL comparison of an unsigned value is always true
> > > fix CID: 1454642
> > >
> > > Signed-off-by: Steven Liu <lq at chinaffmpeg.org>
> > > ---
> > >  libavfilter/vf_delogo.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/libavfilter/vf_delogo.c b/libavfilter/vf_delogo.c
> > > index 376c5e850f..3678548353 100644
> > > --- a/libavfilter/vf_delogo.c
> > > +++ b/libavfilter/vf_delogo.c
> > > @@ -168,7 +168,7 @@ static void apply_delogo(uint8_t *dst, int dst_linesize,
> > >                   botleft[x-logo_x1-1]  +
> > >                   botleft[x-logo_x1+1]) * weightb;
> > >              weight = (weightl + weightr + weightt + weightb) * 3U;
> > > -            interp = ROUNDED_DIV(interp, weight);
> > > +            interp = (interp + weight >> 1) / weight;
> >
> > By the macros definition:
> > #define ROUNDED_DIV(a,b) (((a)>0 ? (a) + ((b)>>1) : (a) - ((b)>>1))/(b))
> >
> I've update the ROUNDED_DIV to:
> #define ROUNDED_DIV(a,b) (((a)>=0 ? (a) + ((b)>>1) : (a) -
> ((b)>>1))/(b)), I guess
> you didn't update the code with this change

Yeah, I'll fetch and update master.

> > I feel it should be:
> > interp = (interp - weight >> 1) / weight;
> >
> > instead of:
> > interp = (interp + weight >> 1) / weight;
> >
> 
> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
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